Sometimes a WordPress theme looks nice and you can consider that the design and functions fits to your needs or perhaps you just consider using it because of a good promotion of the theme. But did you considered checking your theme before actually switch your website layout? You might not know, but a WordPress theme is not just a layout for your website and nothing more. It can really do good or bad things to your website so you might wanna pay attention to the following when changing your WordPress theme in the future, or perhaps test the one you are using right now. Here we go:
I have a premium theme, can't I just trust those ones?
Have noticed lately that premium theme designers often try to show that their product is better because of having much more custom options that the user can switch on and off without touching the code, which is nice if you look at it only from the site owner point of view, but all those are hundreds of conditions, because each option is a multiple condition translated in code and the server will know what to display based on your settings, and that many if's can really slow down your page loading time. There also other important aspects that are not necessary respected when themes are labeled as premium. So you should read further and this brings us to the next point.
Your site loading time (speed)
I made a speed test (25 time for each) for my Twenty Ten child themes against one of the most notorious premium theme designer themes on the same website and same content and my themes were loading faster on average by using 85.16% from the time needed by the other themes. The reason can be a not so well structured HTML, CSS and the many options mentioned above. You can test your website speed for free here and you can change themes to see the difference. Ad we all know, page loading time counts when it comes to keeping your visitors or make them come back.
Cross browser compatibility
Your might be a Firefox or Chrome fan bu i ca assure you that not all your site readers are, you might want to consider checking your site's look in all major browsers. As a site owner or blog author you should have installed all major browsers (Safari, Firefox, Chrome and Opera) but you should not forget about Internet Explorer as well (IE Tester for all versions). Before changing your WordPress theme you should test your website in all these browsers.
All type of contend should look well on your theme
We might have start with this one. If you don't have an online testing environment i do not need to worry, you can always install WordPress locally on your computer by using XAMPP (All OS) and you can import the WordPress test data to your test site. Now you can test your theme against all kind of possible content and make sure it will look nice when switching your live site.
Test your plugins with the new theme
If have some advanced knowledge look into the theme source code to see if the title is tagged H1 only on the frontage and in inner pages your post and page titles will be tagged with H1 (for SEO purposes). Check if your HTML and CSS code validate. Use WordPress theme check plugin to look for hard coded links (beside the link to author) or any other suspicious functions. The plugin will do all the code checks for you and give you a report.
A theme labeled as premium is not a guarantee that everything will work fine after installing it so follow this check list and test it before switch.
You might want to consider spending few extra bucks and order a custom theme for your needs without having many other unnecessary options.
You might be surprised that many free WordPress themes out there will fit your needs and pass the tests.